Microphone-switching system



Jan. 1, 1929. 1,696,897 J. E. AIKEN MICROPHONE SWITCHING SYSTEM Filed June 17, 1924 WITNESSES: I J luv??? 0S6 /7 44 W m ATTORNEY Patented Jan. 1, 1929.

UNITED STATES PATENT OFFICE.

JOSEPH E. AIKEN, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

MICROPHONE-SWITCHIN G SYSTEM.

Application filed June 17,

My invention relates to sound reception systems, and more particularly to sound reception systems for response to a variety of sounds in which severaldifferent types of microphones are used for response to the different types of sounds.

An object of my invention is to provide a sound reception system adapted for use with a plurality of microphones of different characteristics and a thermionic amplifier.

Another object of'my invention is to provide a sound reception system having a number of microphones of different characteristics, an amplifier system and means for avoiding switching sounds when connections between'the amplifier and microphones are changed.

Another object of my invention is to pro vide a sound reception system suitable for use in locations where it is desirable to obtain a sound translation of diffused sounds and at intervals to obtain a sound translation of the voice of a speaker only in the midst of such diffused sounds.

In the art of the reception of sounds and their translation into vibratory electric current it may be desirable to obtain sound translations of sound from-a wide range of sources. There may be occasions such as athletic events that are attended by a large number of spectators during which it is desirable to obtain a sound translation of the cheers and applause of the spectators and, at intervals, to interrupt the translation of such sounds for the translation of sounds of a single spectators voice reporting the progress of the event.

In the prior art, it is customary to use an amplifier system to which a microphone is connected. The amplifier output may then be transmitted to the radio broadcasting station and there used to modulate the radio frequency output. In the prior art, a single microphone was first used, the microphone serving to translate the sounds of the spectators cheers and then being held close to the announcers mouth while he described the progress of the event. This system is inadequate because of the fact that a microphone suitable for reception of diffused sounds of the spectators cheers, is not suit able for the announcers voice, since itdoes not exclude response to extraneous noises and the announcers voice is largely lost and muffied in the extraneous sounds.

1924. Serial No. 720,478.

It has, therefore, been found desirable to use a plurality of microphones and switchin means whereby they may be connected to the amplifier according to the sound whose translation is wanted. It is then possible to use several microphones distributed about the site of the athletic activity, each adapted to respond to the diffused sounds of the spectators cheers. An additional special microphone may be provided of the type shown in my copendlng application, Serial No. 720,477, filed June 17, 1924, suitable for response to a single speakers voice only.

These several microphones are then connected through suitable switching means to the amplifier. A special switch in the amplifier output circuit is provided for automatically opening the output circuit during the interval of changing from one microphone to another.

Other objects and structural details of my invention will be apparent from the following description when read in connection with the accompanying drawing wherein:

Figure 1 is a diagrammatic view of a microphone device adapted for use in connection with my invention,

Fig. 2 is a diagrammatic sketch of the apparatus and circuits of a switching system in accordance with my invention, and Fig. 3 is a perspective view of the switching means.

Referring to Fig. 1, a double-button microphone has a diaphragm 1 and resistor granular cups '2 and 3 on opposite sides thereof, a battery 4 and a transformer 5 with primary windings 6 and 7 and a secondary winding 8.

Referring to Fig. 2, a plurality of microphones 11,12, 13 and 14 are mounted in cases suitable to cause them to respond to diffused sounds and noises, and another microphone 15 built as described in my previously ment-ioned copending application, suitable for response to the voice of a single speaker only, in the presence of diffused sounds and noises. These microphones contain the elements 1, 2 and 3 of the microphone structure shown in Fig. 1. The microphones 11 and 12 are connected to a switch 16 and the microphones 13 and 14 are connected to a switch 17. The output circuit from these switches is in turn connected to a switch 18, to which is also connected-the microphone 15, and to which is mechanically interlocked a switch 19. An

amplifier 21' that is provided is similar to triode amplifier devices of the prior art. It contains also the battery 4 and the transformer 5 shown'in Fig. 1. Switch 19 is connected by the leads 22 to amplifier 21 and by the leads 23 to a radio broadcasting station 24. The switch 18 is biased to one side by a spring which holds it in such position that the circuit from switches 16 and 17 is connected to amplifier. 21.

In this position, the switch 19 likewise connects the leads 22 to the leads 23.

a The contacts of the switch 19 are arranged so thatwhen switch 18 is thrown, and by means of the interconnection switch 19 also, the contacts of the switch 19 open slightly before the contacts of switch 18 and close slightly after the contacts of switch 18 when the reverse position is reached.

Referring to. Fig. 3, the mounting of switches 16, 17 and 18 is shown, upon a top plate26, and within a box 27. A cable 28 is likewise shown containing the various connecting leads between the switches, the microphones and the amplifier.

My device is designed to be operated at an athletic event, such as a football game or a prize fight, or other public productions, at

which it is desired that the progress of the event-"shall be described by an announcer as the event takes place and that between periods of description, the sounds of the cheering of the crowd or other sounds incident to the production shall be translated. In the installation of the device, microphones 11, 12, 13 and 14 may be distributed about the field or auditorium in suitable positions to receive the sounds of the spectators cheers or of the production. Microphone 15, switches 16, 17, 18 and 19 and amplifier 21 may be placed together under the care of an operator or announcer in such location that the announcer has a clear view of the progress of the event. Y

- Before the event begins, switches 16 or 17 may be thrown suitably to connect the desired microphone to the leads of switch 18. The spring 25 then holds switch 18 in position to connect the circuits from switches 16 and 17 directly to amplifier 21. The switch 19 is likewise kept closed by spring 25 and by the interconnection to switch 18 so that the output of the amplifier 21 is conveyed by transmission leads 22 and 23 to the radio broadcasting station 24. Under these conditions, a translation of the sound of the audience is broadcasted. When the announcer desires to describe the crowd or the preparatory activities, he may throw the switch 18 to its reverse position. In so doing, he disconnects that one of microphones 11, 12, 13 and 14 thatis operative from amplifier 21, and substitutes for it microphone15 which is re sponsive only-to his voice. At the com letion of his announcement-the releases switch .18 which is then returned by spring 25 to its previous position to permit the'translation of the difi'used sounds again.

In the operation of switch 18, troublesome switching noises would ordinarily occur because of the fact that transfer from one microphone to another requires either interruption of the telephone circuits or large changes in resistance of the circuit. In either event, relatively large potential changes have been produced in the secondary 8 of transformer 5 resulting in clicks which are amplified and transmitted as very troublesome current surges which produce objectionable sounds in the receivers of connected telephonic apparatus. The presence of switch 19 avoids this by disconnecting the output line of amplifier 21 from radio apparatus 21 during the time of switching from one microphone to another. The interconnection between switches 18 and 19 and the spacing of their contacts is such that movement of the switch handle of switch 18 opens the contacts of switch 19 first, then open [the contacts of switch 18, next closes contacts of switch 18 to another microphone, and lastly recloses contacts of switch 19. Lines 22 and 23 carry no direct'current component, but only an alternating current copy of the sounds, and interruption of themdoes not produce current surges. When lines 22 and 23 are interrupted, the large potential changes and current surges produced by the amplification of switch clicks are prevented from effecting broadcasting apparatus 24.

By this means, I am able to produce'a sound reception system suitable for use-at an athletic or otherevent whereby the voice of an announceg and the sounds of the spectators can be translated by suitable microphones suitably controlled without the development of switching noises.

While I have shown only a single embodiment of my invention in the accompanying drawings, it is capable of various modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be imposed thereon as are indicated in the prior art or in the appended claims. I

I claim as my invention:

1. A sound reception system comprising in tween, an output circuit therefrom and spring-biased switching means therein mechanically interconnected to said first-mentioned switching means.

3. A sound reception system comprising in combination a plurality of microphones suitable for response to general diffused sounds, a microphone suitable for selective response only to a speakers voice in the presence of noises, an amplifier system having an output circuit, switching means intermediate said microphones and said amplifier, and in said output circuit, and means cooperating with said switching means to prevent the current changes incident to the change from one microphone to the other from reaching the output circuit.

4. A sound reception system comprising in combination a plurality of microphones suitable for response to general diffused sounds,

a microphone suitable for selective response only to a, speake voice'inthe presence of noises, an amplifier system having an output circuit and switchinp means intermediate said microphones and said amplifier and in said output circuit, said intermediate switching means selectively connecting said difi'usely responsive microphones and said selectively responsive microphone to said amplifier system, said outputcircuit switching means being; so interconnected with said intermediate switching means that said output circuit is opened during a transfer of connections to said amplifier between said ditfusely responsive microphone to said selectively responsive microphone.

In testimony whereof, I have hereunto subscribed my name this 3rd day of June, 1924.

JOSEPH E. AIKEN. 

